1. Field of the Invention
The invention relates to a punch-bending machine including a plurality of slide assemblies which interact for the non-cutting deformation of wires or strips, each unit being composed of a bedplate which can optionally be mounted in various positions and on which a slide carrying the tool is guided so as to be displaceable in the longitudinal direction, with a cam plate or crank which is rotatably mounted on the bedplate engaging at the slide. 2. Field of the Invention
Automatic punch-bending machines are summarized, particularly with respect to their known drives, in the German periodical "Drahtwelt" [Wire World], 1983, No. 4, pages 90-92. These automatic punch-bending machines usually include a laterally preceding intake station for the precisely controlled intake of a continuous piece of material and, following it, one or a plurality of punching devices. Additional devices, such as, for example, welding devices or the like, may also be provided.
Among punch-bending mechanism equipped with mechanical drives, those equipped with a central gear are widespread. These machines usually have a vertically placed clamping table which has a round window in its center in which is mounted the disk-shaped central gear equipped with teeth at its frontal face. The slide assemblies are arranged around the central gear. To drive the slide, each slide assembly is equipped with a cam plate or crank fixed to a gear and these gears all mesh with the central gear. Although this ensures absolute synchronism at all speed settings, the obligatory circular arrangement of the slide assemblies and the limitation of slide movement in one plane resulted in difficulties in connection with the manufacture of complicatedly bent pieces. The operating range of the tool in the center of the central gear is relatively small.
DE-OS No. 2,527,088 discloses a drive for slide assemblies by means of a series of successive gears, each driving the next one. In this case, the bending center can be shifted from the center of the assembly plate. The position of the slide assemblies is not dependent upon the pitch of a central gear. However, the extraordinary stress on the gears at the beginning of the drive chain is a drawback. It results in great wear and a relatively early change in synchronism.
Also known are the so-called four-shaft machines (German Periodical "Drahtwelt" [Wire World], see above). Here, four shafts are arrnaged as a frame around a usually longer working field and drive the slide assemblies. Although in these machines, the movements of the tool can also be reliably coordinated, the resulting structures are heavy and employ rigid tool systems which often necessitate changes of direction in the slide assemblies.
While in the above-described machines the tool slides move essentially in one plane, DE-OS No. 2,435,996 discloses a punch-bending machine which has freely movable slide assemblies. In these machines, the cam plates of the slide assemblies are either driven from a central drive by means of flexible rotary shafts or a plurality of cam plates are combined on a common drive shaft and flexible push-pull cables trasnfer the lifting movements picked up from the cam plates directly to the tool slides. These machines exhibit good synchronism and are quickly and easily changed to new workpiece shapes. However, their weak point is probably the limitation of the deformation forces that can be generated. Also, this type of structure is presently available only for wires up to 8 mm.
The punch-bending machine disclosed in DE-GM 1,959,907, in which each slide assembly has its own hydraulic drive piston to move the tool slide, exhibits the same advantage of great flexibility. However, the control of these hydraulic drives requires an extremely complicated valve mechanism and it has not yet been possible to realize perfect synchronism and simply coordination of movements. Additionally, the relatively rigid hydraulic line connections are an impediment and, with the large number of line connections involved, the danger of leakages cannot be overlooked. Pneumatic working cylinders which can be operated by way of flexible lines are even more difficult to synchronize and do not produce sufficient deformation forces.